Celeriac, also called turnip-rooted celery or knob celery, is a variety of celery cultivated for its edible roots, hypocotyl, and shoots. It is sometimes called celery root.
It was mentioned in Homer's Odyssey as selinon.
Celeriac is a root vegetable with a bulbous hypocotyl. In the Mediterranean Basin and in Northern Europe, celeriac grows wild...
more on Wikipedia